Method and apparatus for manufacturing finned heat exchangers

ABSTRACT

A method and apparatus for producing highly effective heat exchanger elements of the type which comprise corrugated surface enlarging members of strip material fixed to thin-walled substrates. The strip material, which can be either precorrugated or corrugated synchronously with the heat-exchanger element manufacturing process and which has a thickness of from 50-10 Mu m, is advanced concurrently with a substrate material to a station at which the strip is lightly held in firm abutment with the substrate material by means of an impringing stream of gaseous medium and simultaneously metallurgically bonded to the substrate. The composite product is then cut into lengths to form finished heat exchanger elements.

United States Patent [1 1 Jonason et al.

[451 July 17,1973

[ METHOD AND APPARATUS FOR MANUFACTURING FINNED HEAT EXCHANGERS [75]Inventors: Karl Gunnar Jonason; Karl H arry Karlsson, both of Vasteras;Ake

Gustaf Vilhelm Remning, Finspang, all of Sweden [73] Assignee: GrangesEssem Aktiebolag, Vasteras,

Sweden [22] Filed: Feb. 4, 1971 [21] Appl. No.: 112,732

[30] Foreign Application Priority Data Feb. 5, 1970 Sweden 1498/70 [52]US. Cl... 29/157.3 A, 29/202 R, 29/493,

[51] Int. Cl..... B21d 53/02, 823k 5/22, 823k 31/02 [58] Field. ofSearch 29/l57.3 A, 157.3 AH,

29/l57.3 B, 493, 202 R; 228/4 [56] References Cited UNITED STATESPATENTS 2,332,368 10/1943 Burtenshaw 29/493 X 2,794,243 6/1957 Schweller29/l57.3 B X Primary Examiner-Charles W. Lanham Assistant Examiner.-D.C. Reiley, III Attorney-Waters, Roditi & Schwartz fixed to thin-walledsubstrates. The strip material,

which can be either pre-corrugated or corrugated synchronously with theheat-exchanger elementmanufaeturing process and which has a thickness offrom 50-10um, is advanced concurrently with a substrate material to astation at which the strip is lightly held in firm abutment with thesubstrate material by means of an impringing stream of gaseous mediumand simultaneously metallurgically bonded to the substrate. Thecomposite product is then cut into lengths to form finished heatexchanger elements.

15 Claims, 1 Drawing Figure PAIENTEDJULIHQ v 3,745,631

v 20 19 18 17 5 56 35 53 32 3O 26 29 27 25 22 I 4 B 1 W H METHOD ANDAPPARATUS FOR MANUFACTURING FINNED HEAT EXCHANGERS it has previouslybeen proposed to use an elongated heat-exchange element blank forconstructing heatexchangers intended for cooling or heating purposes,preferably for use in motor vehicles, the blanks being provided alongthe length thereof with surface enlarging means in the form of metalstrips folded transversely to the long axis thereof and which are inmetallic contact with the basic profile.

The present invention relates to a method of mechanically manufacturingin elongated lengths blanks of the aforementioned type provided withsurface enlarging means for heat-exchange elements intended forheatexchangers for cooling or heating purposes, preferably for use inmotor vehicles.

The method of the invention is mainly characterized by the fact that ametallic basic profile of arbitrary length is advanced in onelongitudinal direction thereof together with at least one metal stripwhich has been permanently folded transversely of its long axis, andthat said strip is guided with the wave crests of one side thereof inabutment with the advancing basic profile, that the abutting wave crestsare permanently metallurgically bonded with the basic profile and thatthe basic profile bonded to said surface enlarging means is cut intodesired lengths to form finished heat-exchange elements for use in theconstruction of the heatexchanger.

The invention also relates to an apparatus for manufacturing elongatedheat-exchange element blanks in accordance with the method of theinvention.

The apparatus of the invention is mainly characterized by means forfeeding the basic profiles in one longitudinal direction thereof alongan individual movement path and means for advancing corrugated metalstrip material together with said profile in a manner whereby saidcorrugated material is brought into abutment with the basic profile andcarried by its movement, and means for metallurgically bonding thecorrugated strip with the basic profile, and means for cutting the basicprofile with the corrugated strip mounted thereon into desired lengths.

The invention will be described in more detail with reference to anembodiment thereof diagrammatically illustrated in the accompanyingdrawing, further characterizing features of the invention beingdisclosed in conjunction therewith. The drawing illustratesdiagrammatically and in plan view an exemplary embodiment of a plant forcarrying out the method of the invention, I

In the exemplary embodiment of the plant there are included two feedrollers 10, 11 of which one is driven by a motor 12 over appropriatetransmission means, for example a belt or chain transmission 13. Therollers 10 and 1 1 are arranged to feed an elongated basic profile 14,preferably at a determined speed, in the direction of arrow A, the basicprofile being either of solid or hollow construction. Basic profilesmanufactured continuously by known processes such as, for example, byextrusion or by shaping strip material into basic profiles, can beconnected directly to the process of the invention without trespassingfrom the purview thereof.

For reasons of space, however, it is often advantageous to produce andpre-treat basic profile material,

irrespective of whether it is solid or hollow, in separate processes andto convey the finished basic profile material from a place of storage toa starting station, from where it is fed between the rolls 10 and 11.

It is assumed in the following description that the basic profilematerial 14 fed in the direction indicated by arrow A in the drawing haspreviously been provided with a coating of an appropriate solder. It ispreferred that the material from which the profile is made comprisescopper or copper alloy, which is advantageous from the aspect of heatand soldering, although the selection of metal is naturally notrestricted thereto, but can be broadened to include other metalssuitable in the present context.

In the exemplary embodiment, the profile material 14 is fed through apre-heat' furnace or melt zone 15, wherein the solder on the profile isheated to a molten condition before leaving the furnace or zone 15through the discharge openings 16, whence it is continuously moved in arectilinear path in the direction of arrow A between two feed rollers 17and 18. The profile passes from the rollers 17 and 18 through a combinedcooling and holder-down means, generally indicated at 19, to be finallycut by means of cutting means 20 which operate according to theprinciple of flying shears, i.e. are able to move in the directionsindicated by double arrow B. The cutting means and associated guidemeans can be adjusted with respect to the length of stroke and,moreover, the speed of movement of said cutting means can be adjusted tocoincide with the speed at which the basic profile is advanced duringthe cutting period.

It is intended with the illustrated plant that the basic profile 14shall be provided on two sides thereof with surface enlarging means inthe form of corrugated metal strip, suitably comprising metals of veryhigh thermal conductivity. When applying the method of the presentinvention, foil strip having thicknesses, for ex ample, of between and10 m, suitably between 35 and 15pm, and preferably 25am, can be used.Corrugated metal foil strip of such extreme thickness is, however,liable to become deformed and should therefore be processed mechanicallyto prevent the occurrence of deformations during the treatment processand during their period of conveyance to a position where they mergewith the basic profile located between the feed rollers 17 and 18.

As will be seen from the drawing, duplicate devices are arranged oneither side of the advanced profile 14 for handling and conveying thecorrugated strip material to the position between the two rollers 17 and18. The two handling and conveying means are generally indicated at iand II respectively and, since these devices are completely identical toeach other, although in mirror image, only the device 1 will bedescribed in detail, while it is at the same time assumed that thefunction of the two devices coincide in-all parts thereof. The referencenumeral 21 indicates metal strip, suitably of copper or copper alloy,moving in the direction of arrow C. This strip, which within the scopeof the invention may have any suitable thickness, is presumed in thedescribed example to have a foil thickness. The strip 21 is fed in themanner shown in the drawing into a folding means comprising two meshingcogs 22 and 23 driven by a motor 24. The strip is corrugated during itspassage between the two cogs and leaves said cogs in the form of a coilstrip 25 folded transversely of its longitudinal axis, the strip thenbeing guided into a socalled compacting means indicated generally at 26.The compacting means includes two groups of feed rollers, i.e. rollers27 and 28 driven by a motor 29 and rollers 30 and 31 driven by a motor32. The drive motors are thus arranged to drive their respective pairsof rolls in a manner whereby the roll pair 30, 31 has a lower peripheralspeed than the roll pair 28. Consequently, during its passage betweenthe two pairs of rolls, the corrugated foil strip will be subjected to acontinuous compression force in the direction of movement, owing to thedisparity in peripheral speeds between the two pairs of rolls.

The longitudinally compressed, corrugated strip 25 is passed from thecompacting means 26 between a pair of guide structures 33 and 34 towardsthe nip between feed rollers 17 and 18, the guide 34 presenting a cutaway portion 35 in which projects an applicating roller 36 for a fluxingagent, which is applied to the wave crests of the passing corrugatedstrip 25. The fluxing agent 37 is sprayed onto the rotating roll 36 froma suitable nozzle 38, as shown in the Figure, the roller transferringthe flux to the strip. The corrugated fluxed strip leaving the guidestructures 33 and 34 is then entrained by the feed roller 17, whichconstantly rotates in the direction of arrow D, and is guided by saidroll into abutment with the basic profile 14 passing between the rollers17 and 18, the fiuxed wave crests coming into contact with the moltensolder on the basic profile 14. The basic profile and the corrugatedstrip are then fed into the holderdown means 19, which mainly comprisestwo guide structures 39 and 40 in the form of hollow boxes, the guidesurfaces of which are provided with perforations 41 and 42. A gaseousmedium such as air is introduced into the boxes through nozzle 43 and 44respectively and caused to impinge on the corrugated strip. The gaseousmedium cools the solder to the point of solidification and at the sametime exerts a holding force on each of the two corrugated strips,thereby maintaining the strips in firm abutment with the sides of thebasic profile. When the solder has solidified, the discharged basicprofile will be provided with a permanently fixed continuous surfaceenlargement in the form of at least one corrugated metal strip which isin metallic contact with the basic profile. The basic profile providedwith the surface enlargement as afore described is then cut intosuitable, predetermined lengths by means of the cutting device 20, whichtogether with its driving assembly is capable of moving in the directionof double arrow B at selective length of stroke and at a speed, whenmoving in the direction of feed of the basic profile, which coincideswith the speed of the basic profile during the cutting period.

It also lies within the scope of the invention to provide the basicprofile with solder over the whole of the part where soldering is totake place, or only at the calculated points of contact for thesubsequently arriving corrugated strip. Further, the corrugated stripmay also be provided with solder. In accordance with an alternativeembodiment of the invention, the corrugated strip may be produced in aseparate process or in a process directly connected to the describedmethod. Thus, it is possible to produce the strip and corrugate the samein directly connected processes.

With respect to the basic profile, this may also be produced separatelyin a special process or also in a directly connected process. Theprofile used may either be solid or a hollow profile. In the latterinstance, the profile may, for example, be made of a metal strip.

Furthermore, it is important that metals are selected; with respect tothe profile and the corrugated strip, which can be metallurgicallybonded together in a suitable manner. In the case of the basic profile,copper alloy, preferably copper-zinc-alloy is suitable, while in thecase of the corrugated strip a copper alloy, preferably extremely purecopper is a suitable metal.

The invention is not restricted to the shown and described embodimentthereof but can be modified within the scope of the following claims.

What is claimed is:

l. A method for series manufacture of high-effective heat-exchangeelements for heat exchangers intended for cooling or heating purposes,preferably for use in motor vehicles, and being of the type whichcomprise a cylindrical, metallic relatively thin-walled basic profileprovided with a longitudinally extending surface enlarging member whichis in the form of a metallic strip corrugated transversely of thelongitudinal axis thereof and which is in intimate heat conductingcontact with the basic profile, comprising the steps of providing, priorto the actual manufacture of the elements or in conjunction with saidmanufacture, desired lengths of said cylindrical profile, advancing saidlengths of cylindrical profile in a known manner in series in one enddirection thereof, advancing concurrently therewith extremely thin stripmaterial which has been permanently corrugated transversely of itslongitudinal axis, guiding the corrugated strip material successivelyinto abutment with the basic profile, impinging a stream of a gaseousmedium such as air against the corrugated strip material in order toexert a holding force so that the crests of the corrugations are held infirm abutment with said basic profile and simultaneously establishing apermanent metallic bond between the basic profile and said crests, andfinally cutting the basic profile with the surface enlarging memberpermanently fixed along the length thereof into desired lengths to formfinished heat-exchange elements.

2. A method according to claim 1, wherein the permanent metallic bondbetween the corrugated strip material and the basic profile is effectedby a continuous soldering operation and wherein the gaseous medium 5. Amethod according to claim 3, wherein the solder-coated basic profile ispassed through a heating zone to melt the solder and maintain it in amolten state at the time of contact with the advancing corrugated stripmaterial.

6. A method according to claim 4, wherein immediately upon contact ofthe corrugated strip with the basic profile and the solder appliedthereto the corrugated strip is held lightly pressed against the basicprofile by directing a gaseous medium against said strip material whilecooling the solder to establish a permanent metallic joint between thebasic profile and the corrugated strip material.

7. A method according to claim 1, wherein the strip material iscorrugated in a process directly connected with the heat-exchangerelements manufacturing process.

8. A method according to claim 7, wherein the strip material is producedand corrugated in processes directly connected with the heat-exchangerelement manufacturing process.

9. A method according to claim 1 wherein said cylindrical profilecomprises a solid basic profile which is advanced in its longitudinaldirection and provided with said surface enlarging member.

10. A method according to claim 1, wherein the basic profile comprises acopper alloy, preferably a copperzinc alloy and the corrugated stripmaterial comprises a copper alloy, preferably very pure copper.

11. A method according to claim 1, wherein the corrugated strip materialis a metal foil having a thickness of the order of SO-lOym, preferably35-l5p.rn, suitably 25 pm.

12. An apparatus for series manufacture of highlyeffective heat-exchangeelements for heat exchangers intended for cooling or heating purposes,preferably for use in motor vehicles, and being of the type whichcomprise a cylindrical, metallic basic profile provided with alongitudinally extending surface enlarging member which is in the formof a metallic strip corrugated transversely of the longitudinal axisthereof and which is in intimate heat conducting contact with the basicprofile, said apparatus comprising first feed means for feeding saidbasic profile in one end direction thereof in an individual movementpath, second feed means for feeding said corrugated metallic stripconcurrently with said basic profile into abutment with said basicprofile and entrained in the movement thereof, blower means positionedin the path of movement behind said corrugated strip and arranged toimpinge a stream of gaseous medium against the corrugated strip materialpassing thereby so as to maintain said strip in abutment with andcorrectly distributed along the surface of the basic profile, and meansoperative in coordination with said blower means to successivelyestablish metallic bonds between the basic profile and the crests of thecorrugations of said strip during passage of said basic profile and saidstrip past said blower means.

13. An apparatus according to claim 12, wherein the means forestablishing a permanent metallic bond between the basic profile and thecorrugated strip material comprises a) a zone for melting or heating thesolder composition applied to the basic profile, said zone being locatedin the movement path of the basic profile before the blower means, andb) the blower means in its simultaneous capacity as the cooling zone forsaid solder composition.

14. An apparatus according to claim 12, wherein there is arranged behindthe combined holder means and cooling zone so called flying shear meansthe length of stroke of which can be adjusted and which is arranged tobe moved at the same speed as the basic profile during the cuttingperiod.

15. An apparatus according to claim 12, wherein means for corrugatingthe strip material is placed in connection with the corrugated stripmaterial feeding means.

2. A method according to claim 1, wherein the permanent metallic bondbetween the corrugated strip material and the basic profile is effectedby a continuous soldering operation and wherein the gaseous medium isused to cool the joint created between the strip material and the basicprofile.
 3. A method according to claim 2, wherein the basic profile isprovided with a solder composition and the solder heated to a moltenstate prior to bringing the corrugated strip material into abutment withthe basic profile.
 4. A method according to claim 3, wherein the basicprofile is provided at at least the estimated positions of contact withthe advancing corrugated strip with a solder composition simultaneouslyas it is advanced along its movement path.
 5. A method according toclaim 3, wherein the solder-coated basic profile is passed through aheating zone to melt the solder and maintain it in a molten state at thetime of contact with the advancing corrugated strip material.
 6. Amethod according to claim 4, wherein immediately upon contact of thecorrugated strip with the basic profile and the solder applied theretothe corrugated strip is held lightly pressed against the basic profileby directing a gaseous medium against said strip material while coolingthe solder to establish a permanent metallic joint between the basicprofile and the corrugated strip material.
 7. A method according toclaim 1, wherein the strip material is corrugated in a process directlyconnected with the heat-exchanger elements manufacturing process.
 8. Amethod according to claim 7, wherein the strip material is produced andcorrugated in processes directly connected with the heat-exchangerelement manufacturing process.
 9. A method according to claim 1 whereinsaid cylindrical profile comprises a solid basic profile which isadvanced in its longitudinal direction and provided with said surfaceenlarging member.
 10. A method according to claim 1, wherein the basicprofile comprises a copper alloy, preferably a copper-zinc alloy and thecorrugated strip mateRial comprises a copper alloy, preferably very purecopper.
 11. A method according to claim 1, wherein the corrugated stripmaterial is a metal foil having a thickness of the order of 50-10 Mu m,preferably 35-15 Mu m, suitably 25 Mu m.
 12. An apparatus for seriesmanufacture of highly-effective heat-exchange elements for heatexchangers intended for cooling or heating purposes, preferably for usein motor vehicles, and being of the type which comprise a cylindrical,metallic basic profile provided with a longitudinally extending surfaceenlarging member which is in the form of a metallic strip corrugatedtransversely of the longitudinal axis thereof and which is in intimateheat conducting contact with the basic profile, said apparatuscomprising first feed means for feeding said basic profile in one enddirection thereof in an individual movement path, second feed means forfeeding said corrugated metallic strip concurrently with said basicprofile into abutment with said basic profile and entrained in themovement thereof, blower means positioned in the path of movement behindsaid corrugated strip and arranged to impinge a stream of gaseous mediumagainst the corrugated strip material passing thereby so as to maintainsaid strip in abutment with and correctly distributed along the surfaceof the basic profile, and means operative in coordination with saidblower means to successively establish metallic bonds between the basicprofile and the crests of the corrugations of said strip during passageof said basic profile and said strip past said blower means.
 13. Anapparatus according to claim 12, wherein the means for establishing apermanent metallic bond between the basic profile and the corrugatedstrip material comprises a) a zone for melting or heating the soldercomposition applied to the basic profile, said zone being located in themovement path of the basic profile before the blower means, and b) theblower means in its simultaneous capacity as the cooling zone for saidsolder composition.
 14. An apparatus according to claim 12, whereinthere is arranged behind the combined holder means and cooling zone socalled flying shear means , the length of stroke of which can beadjusted and which is arranged to be moved at the same speed as thebasic profile during the cutting period.
 15. An apparatus according toclaim 12, wherein means for corrugating the strip material is placed inconnection with the corrugated strip material feeding means.